Freeze and Hot Tap Case History #9

Objective: Hot tap 3 ½ tubing full of scale plugs to safely remove tubing from well.

Well Information: 2600 Meter sour well pressure between shale plugs unknown. Casing pressure zero mPa.

Procedure: All operations performed masked up. Install 3 ½ inch tubing clamp, working ball valve and hot tap drill with ¾ inch bit. Pressure test with baker pump to 15 mPa based on well history. Leave 10 mPa on assembly drill ¾ inch hole, once hole drilled pressure dropped to zero. Rig out hot tap equipment and tie into testers, bleed off. Tie in to rig pump and attempt to pump fluid to determine if any more shale plugs in tubing. Unable to break circulation- bleed off pressure, rig out pumping equipment, confirm no pressure between hot tapped joint above collar of next joint. Break out joint and install a TIW valve in next joint in well. Continue above procedure until circulation obtained and tubing clear of shale plugs. In all 33 hot taps were performed with pressures of up to 3000 kPa and 16% sour gas to be found.

Time on location: 36 hours